Cellulose-ether film and composition for making the same



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Patented June 1-1, 192:;

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nonnfor ROCHESTER; NEW YORK, AssIGNoa 'ro- EAsrMAN xonAx COMPANY, osnocnns'rna, EW YoainA ooaroaA'rroN or NEW-YORK.

.eELLuLosn-arrinn FILM. AND comrosrrIoN FOR MAKING THE sAmni --No Drawing.

..Thisgi'nvention relates to compositions of matter in which cellulose, ethers, suchas water-insoluble ethyl c ellulose,[are combined or mixed with other substances which im- 5 part not only low infiammability, but likewise give compositions the other properties of which are also highly advantageousin the plastic and analogous, arts, such, for instance, as the film or varnish arts. I i

One objectof the invention is to provide cellulose ether "films having not only all of the. ordinary desirable qualities of films for photographiepurposes, but also having unusually} low infiammability and extremely highj resistancesto deterioration by heating.

Another object of. theinvent-ion is to provide permanently transparent, strong, flexible sheets or films of desired thinness, which are substantially waterproof, are unaficcted byf-"ordina'ry photographic fluids, are subst'ant'ially colorless, are substantially without "harmful action upon light-sensitive photo.- graphic coatings, are of low inflammability and highly resistant to prolonged heat. Another object of the invention is to provide compositions capable of easy manipulation in film making, varnish making, or allied plastic arts. Another object is to provide compositions which will not injure or be in-' jure'd :by the substances or surfaces with which they are associated during manufacture,. storage. or use.- Other objects will hereinafter appear. 1 In U. S. Patent No. 1,188,376, Lilienfeld,

June 20th, 1916, there are disclosed a series of alkyl ethers of cellulose. Certain of these are particularly insoluble in water, and the present invent'on finds its chief value in connection with ethers having this property, 40 such as water-insoluble ethyl cellulose, films of which have small shrinkage characteristics, after treatment in photographic baths. In U. S. Patent No. 1,583,709, \Vebb, May 4th, 1926, there are-disclosed films of'such cellulose others in which the ordinary desirable qualities-of photographic film base are combined with resistance to .prolon ed heating, this result being brought about y maintainin an alkalinity in excess of Ph,. It is desirable that such films,'-especially motion picture films, be capable of withstanding heating without becoming brittle. Whether or not film'swill possess this property can be foretold with practical accuracy by testa ing samples, say by heating them for weeks.

Applieation fled Au ust 9, 1m. serial No. 128,337.

and even months'at a continuous tempera: I ture of 0.. Films which remain usefully flexible after such a severe test are capable of withstanding the conditions met with in use.

I have found that these qualities of-the films may be maintained and yet the inflammability greatly lowered by incorporating in such films and in the compositions out of-- -which theyare made, one or morev of the brom-nucleo substitution products of benzol and itshomologues, especially those which .are liquid at ordinary temperatures and have 1 saturated. side chains, such, for example, as mono, di, tii, or other poly brom benzols,

. toluenes, xylenes, mesitylenes, ethylbenzenes, cumenes and cymenes. .Where ortho, .meta or para isomers exist, they are all usable. On account of their relative cheapness and simplicity of manufacture, I prefer monm brombenzol, .parabromtoluene, and ortho bromtoluene. All of these substances, when mixed into the film-making compositions, should befree from free bromine and free hydrobromic acid. Otherwise" they will cause sufficient discoloration to make the film undesirable for photographic purposes,

- will cause deterioration of any photographic emulsions placed upon the film, and will destroy the alkalinity upon which the resistance of the film to prolonged heating de pends. If the brominated compounds are initially purified from free bromine and free hydrobromic acid and are incorporated in filmshaving an alkalinity greater than Pi there is no acidity in the film-making solution, nor in the film, nor does this condition develop during the normal storage of the solution or during the normal useful life of the film.

I shall now give one example of myiinvention' by way of illustration, but it will be understood that the invention is not limited to these details, except as indicated in the appended claims. parts by weight of water-insoluble ethyl cellulose containing sufiicient alkali, say by undergoing the treatment given in lines 78 to 920i page 1 in the above cited Webb patent, arerdissolved along with 5 to 50 (say 10 parts) of monobrombenzol in 300 to 500 parts of a volatile common solvent. The latter may usefully comprise a mixture of methyl acetate and methyl alcohol, the weight of the methyl acetate be g approximately nine t' g s t e no weight of themeth 1 alcohol. Of course,

the ingredients of t esolvent are of sufli-- cient'purity'to avoid acidifying the composition. This ,cjom osition is suitable for coating, from which "the volatile solvent flexible sheet, -which is stripped ofi and o'therwisei treated'in a manner well lmown';

- 'substantially the ,following: 100 parts by. g weight of water insoluble ethyl-cellulose 10 spreading upon a lm'eforming'surfac'e-in a evaporates s'ufiiciently to leavea transparent,

to-those skilledin' this art. :In place of the monobromhenzol, an equal'n'umber of parts bye-weight can be substituted of any one of the- 'brominated bodies mentioned herein-fabove, or mixtures ofjthem. By reason of the fact that these brominated products are '1 of the 'nucleotype, having thebromine atoms directly bonded to the-ring of carbon atoms,

- they are particularly stable. v

w The ingredients in the film-forming com-1 position: are th'orough'ly'mixed and may be filtered if desired. WVhon more fiowable solutionsrarejdesired, or when. the compositions are to :he employed as.lacquers,,thc volatile solvent may be increased; until the desiredflyi'scosity is obtained, or volatile liquids, such" as.l. benzol,-alcohol, and the like mayjbelmdded to the thinner. Along with I the ingredients mentioned above, I may add one oi ;.mo're supplementary organic bodies .7 of. oi1l {slight volatility which enhance the flexib' ifty" ofthecoinpositions and'regulate the preparation; of film'jtherefrom; but such bodies are, "otessential-b Examples of them i ty' ate, the various amyl alcohols, the '-'vai:'ious.iibutyl alcohols, and

, mixtures of the1n'-.- -Of course, these ingredients-are also s'ufiiciently pure to be non-acid;

Filmsfprepar'ediromthe hereinabove (lescribed ;compos' itions are flexible, smooth,

transparent, strong, "substantially colorless, substantially waterproof, are unaffected by ordinary )hotogra'phic baths, and in addition, com ine'unexpectedly low inflammability,with-highx'reslstance against brittle- [ness' upon prolonged-heating at 65 or equivalent conditions .in" actual use. 7 "amount of alkali .in' 'the film is, of course,"

,1 insufficient to: impair their transparency.- ,Q Having'thu'sf'described my invention, what I claim as new and desire to secure by ,.-Let .l vters Patent is 1. A fiowable composition comprising'a waterinsoluble cellulose= ether, a brom-nucleo s'ubstitutionproduot of benzol and its 'homologues, which product is substantially J free fromuncombined bromine and hydro- 5 tbromicaci'd, and a solvent-commonto'said ingredientg said composition being stabilized by the presence therein of inorganic" ,alkali; which creates an alkalinity in the composition inexcess of Ph,, -the proportions being such that .a product formed'therefrom "willhave the properties of {high transparencies," freedom from accidental color, inert-- toward photograp'hic emulsions and. high'i'esistancetoheating; 1

- 2; A. composition "of matter comprising 'partsofmonobrombenzol substantially ree from-funco'mbined bromine and hydrobromic acid, and more than 300 parts of a volatile common solvent, said composition comprising sufiicient inorganic alkalito give it an alkalinity in excess of Ph,.

alkali to giveit analkalinity in excess of P11 the proportions being'such that a prod-- riot-formed therefrom will have the properties. of? high transparencies, freedom from accidental color, me'rtness toward photoa graphic emulsions m l' si flnce to heating.

4. As an article of manujltacture, a film comprising colloidized' water-insoluble 'cellulose other and "a 'brom-nucleo substitution product of benzol and its homologues, said product being substantially free from uncombined bromineand hydrobromic acid, said film having'distributed therein suflicient inorganic alkali to give thefilm, an al-. kalinity in excess of Ph,, the-proportions of the ingredients being such that the film is floxiblejtrans'parent andincl't to photographic emulsions. r

5. A S': ;;&Ift Ij-til6 of manufacture a film comprising. colloidlzedwater-insoluble ethyl ccelh'ilo'scangi'monobromhenzol free'from uncombmedjbromlnejand hydrobromic acid,

said film having jiiniformly distributed therein suflicientg norganic alkali to give-the film an alkalmityjin-excess of P11 the 1 amount of alkalibeing insufiicient to impair the transparency of the film, the proportions n ofthe ingredients being such that the film is flexible, ,transparentfand inert to photo graphic emulsions.

:Signed. atRoche'ster, York, thi 9 "-1 dayofJuly',-' 1926.- a 1 saEWaRT CARROLL. 

